1. Field of the Invention
The present invention generally relates to integrated circuit devices, and more particularly, to methods and systems for preventing unauthorized access to proprietary information contained in the integrated circuit devices after the devices have left the manufacturing facility.
2. Description of the Related Art
Many integrated circuit (IC) devices, such as systems on a chip (SOC) and other types of very large scale integration (VLSI) and ultra large scale integration (ULSI) devices include interfaces that allow for access to the internal registers and other components of the devices. This access to the internal components of the devices allows for testing and troubleshooting of the devices, which is primarily conducted during the manufacturing process and in the development of the device, for optimization of performance. In addition, interfaces may allow registers to be programmed to activate a particular mode, for example, reconfiguring the I/O of a processor to increase on chip bandwidth for a given application. Examples of such interfaces include level-sensitive scan design (LSSD) scan chains and the JTAG interface, named after the Joint Test Action Group committee that established the test access port and boundary-scan architecture defined in IEEE Standard 1149. Testing algorithms that utilize such interfaces to modify and examine the internal workings of the device by reading/writing the device's internal registers are well known.
However, these test interfaces often provide an interface or “backdoor” for a hardware hacker, i.e., a person unauthorized to access information contained in the device, to gain access to the device, and more particularly, to gain access to the manufacturer's proprietary information embedded in the device. Although hacking may not be a substantial issue for many devices on the market, as there may be little economic or emotional gain to breaking into those devices, for other devices, such as those used in video game consoles, satellite decoders, and the like, there is generally substantial economic gain to be had through hacking into the internal proprietary information of these devices, as hacking can be used, for example, to enable or unlock features intended to be paid-type upgrades. In these types of systems, encryption is often employed in an attempt to protect proprietary data (e.g., copyrighted game data or subscriber-only media signals). However, recent advances in hacking techniques have allowed hackers to overcome many encryption processes through use of the test interfaces noted above.
Further, in conventional integrated circuit device manufacturing, systems on chips (SOCs) and other devices are designed and produced for relatively specific purposes. In this type of a manufacturing process, inherently there are chips manufactured that are more advanced than others, and generally speaking, the more advanced chips may often include the ability to perform the functions of the lesser advanced chips. In this situation, it is often practical from a manufacturing cost standpoint to simply manufacture only the more advanced chips and use these chips for all applications, as the cost per chip is often negligible between the more advanced chips and the lesser advanced chips. In this situation the more complex chip may be implemented into configurations of lesser complexity with the unused or more advanced portions or modules of the chip disabled. Similarly, when a more complex chip is implemented into a lesser complex application, the manufacturer has the option of enabling the disabled portions of the chip to upgrade the chip as demands necessitate.
However, from a business standpoint, manufacturing a single chip for multiple complex applications and disabling the more advanced portions of complex chips used in configurations of lesser complexity can be problematic, as chip hackers may exploit the use of the more advanced chip in a configuration of less complexity, e.g., the hackers will use unauthorized methods to unlock the disabled modules of the chip. The unauthorized access to the disabled portions of the chip decreases the manufacturer's revenue such that the manufacturing cost savings incurred as a result of manufacturing only the more advanced chips are often eliminated. Further, in some cases, hacking may result in degradation of device reliability and possibly catastrophic failure (e.g., device overheating) if an operating frequency is increased. This may be particularly problematic for a manufacturer if the hacker is not the end user, for example, if the hacker is in the supply chain and passes on a hacked device to an unsuspecting end user who then returns it to the manufacturer or seeks remedy for damages from the manufacturer.
Further still, with integrated circuit devices and SOCs, once the device or chip has shipped to the end user, the manufacturer no longer has the ability to modify, upgrade or repair the chip without removing the chip from the end user system. This limitation obviously prevents manufacturers from upgrading or repairing chips insitu.
Accordingly, there is a need for methods and apparatus for preventing unauthorized changes or activation of disabled modules or functions of integrated circuit devices once the devices have left the manufacturer. Further, there is a need for methods and systems for preventing unauthorized access to internal device information through test interfaces after the devices have left the manufacturing facility. Further still, there is a need for methods and apparatus configured to allow for insitu modification of device or chip parameters while the device is with an intermediate or end user.